Exercise machines of various types are well known. One way to categorize exercise machines is based on the particular muscle group, limb or joint being exercised. As is well known, there are multistation machines which are capable of exercising several different muscle groups. An example of this type of machine is the Isopower 5000 machine sold by The Toro Company Minneapolis, Minn., the assignee herein. The Isopower 5000 multistation exercise machine includes a pair of magnetic particle brakes which are freely adjustable along a pair of arcuate support bars, and are also angularly adjustable with respect to the support bars. Such a machine can provide a wide variety of exercises, including leg extension/curl; chest press; pullover; hip-back/abdominal flex; shoulder press/lat pull-down; declined chest press/rowing; biceps curl/triceps extension; chest cross/rowing; and hip adduction/abduction.
There are also single station exercise machines which are specifically designed to exercise a single joint or muscle group. The present invention is particularly directed to a shoulder and elbow single station machine. However, those skilled in the art will recognize that the elbow and shoulder machine of the present invention could be incorporated into a multistation machine as well. It should also be noted that the preferred shoulder and elbow machine of the present invention can be used for general exercise and also for rehabilitation therapy under the guidance of a trained physical therapist.
As noted above, a preferred embodiment of the present invention is a single-station shoulder and elbow exercise machine. Although the desirable structural and functional features of shoulder and elbow exercise machines may varY depending on the application, i.e., light duty exercise, heavy duty exercise, or therapy, certain desirable features for all types of shoulder/elbow machines can be identified. Of course, a shoulder/elbow exercise machine must be capable of exercising a wide variety of shoulder and elbow movements. While it is fairly easy to exercise the elbow joint, since the elbow provides a simple hinging between the upper and lower arm portions, the shoulder is an extremely complex structure whose multiple articulations result in a range of motion which exceeds that of any other joint, and places unique requirements on a shoulder/elbow exercise machine. Given the complexity ot the shoulder joint, a shoulder and elbow machine should preferably accommodate a wide variety of exercises, including all extension/flexion, abduction/ adduction and internal/external rotation motions of the elbow and shoulder complex.
Arm and shoulder exercise machines should preferably be adjustable. Exercise machines have "resistance units" which are traditionally hydraulic, pneumatic or simply mechanical (e.g., weight stack), as in the case of Nautilus machines and the like. Coupled in some manner to the "resistance unit" is an "exercise arm," the free end of which is grasped by the user and pivoted or translated in accordance with the prescribed exercise. The resistance unit is preferably vertically adjustable to accommodate different table or chair heights user sizes and positions and exercises. In addition, the resistance unit or the entire exercise machine should be angularly adjustable, in a vertical plane, for various orthogonal and diagonal exercises. For dynamometer resistance units that include an armature the axis of the dynamometer's armature must be adjustable so that it is colinear with the assumed axis of rotation of the joint.
Not only should shoulder/elbow machines be adjustable, they should also provide a wide range of motion. Any machine designed to exercise the shoulder must accommodate the natural movement of the joint, for exercise should increase flexibility as well as strength. Movement of the shoulder, in particular, results in a changing user "lever arm". Thus, Applicants perceive that the free end of the exercise arm should carry a "floating" or sliding cuff or grip so that the user's natural motion is not hindered by the exercise arm, but instead the exercise machine itself can dynamically realign itself to the natural joint motion. Applicants have found that a floating hand grip allows for a more accurate torque transfer throughout the range of motion and increases patient comfort through reduced ]oint stress.
Shoulder/elbow exercise machines, in addition to accommodating various natural shoulder and elbow movements, should preferably be portable. It is desirable to have a plurality of therapy tables or beds and only one comparatively expensive piece of shoulder/elbow rehabilitation equipment which can be readily moved from user to user. It should be very easy to convert the exercise machine from the stationary to the mobile mode. And, the mechanism for providing mobility to the exercise machine should be very simple easy to maintain, and not contribute significantly to the cost of the machine. Finally, the exercise machine should be lightweight, well balanced and maneuverable.
Exercise and rehabilitation devices typically include casters or wheels for portability. The casters are lockable or, alternatively, a set of auxiliary legs can be lowered to in effect raise the casters off the floor surface to render the equipment nonrollable. Locking casters are useful in some circumstances, but they are inconvenient since each caster must be individually locked. Further, since only a very small portion of each caster touches the floor the traction provided by locked casters is oftentimes inadequate. Thus, it is perceived that the latter method, i.e., providing a set of auxiliary legs which can be lowered in relation to the casters to provide a stable base, is superior.
Such machines should be stable once transported and adjusted. Shoulder/elbow machines should be capable of providing up to approximately 80 foot-pounds of torque. The machine must not be susceptible to swaying, tipping or sliding, for otherwise the machine will be difficult to use.
Although prior art multipurpose exercise machines are generally useful for their intended purposes including shoulder and elbow exercises they do not include all of the desirable features discussed above. For example the Cybex II machine sold by Cybex, Division of Lumex, Inc., Ronkonkoma N.Y., includes a fixed lever arm i.e. a hand grip or cuff which is fixed to the exercise arm. This fixed lever arm system provides an accurate indication of the force being applied by the user, by measuring the torque at the pivoting end of the dynamometer but tends to restrict the natural motion of the joint since the pivot point of the shoulder changes throughout a motion. The Cybex system also includes a dynamometer which is indeed portable but is unstable and must be clamped to a rather massive and expensive wooden table. In order to use the Cybex dynamometer for elbow and shoulder exercising, the user sits or lays on an expensive therapy table and the user, not the exercise machine, is adjusted depending on the prescribed exercise. Thus, the exercise machine itself cannot be wheeled to a standard bed or chair, but instead must be rigidly clamped to a massive support structure. The Cybex dynamometer cannot be adjusted once it is clamped in place.
Further, the Cybex "UBXT" therapy table which is sold in conjunction with the Cybex dynamometer has a very complex leg support system which includes four casters and four auxiliary legs, wherein the auxiliary legs can be raised or lowered relative to the casters to render the machine mobile or stationary. The means for moving the auxiliary legs includes a complex rod and pivot linkage between a pair of foot pedals and the legs, and the whole mechanism is connected to a shock absorber which is apparently incorporated to control the rate of movement of the auxiliary legs relative to the rest of the therapy table. It is perceived that this auxiliary leg system makes for a cumbersome and complicated table which is quite expensive, heavy and mechanically complex; and that it would be better to use a stationary therapy table in conjunction with a portable and adjustable exercise/therapy device.
Another prior art exercise system commonly used for shoulder/elbow exercise is sold by the Biodex Corporation. While the Biodex machine includes a "floating" hand grip, it is perceived that the grip sliding mechanism is too flimsy for relatively heavy exercising. Also, the Biodex machine like the Cybex machine, is disadvantageous because the resistance unit itself is not portable but is instead connected to a massive support structure. Thus, it is impossible to wheel the resistance unit from one location to another without either moving the rather large and expensive support structure, or having multiple support structures.
While the prior art multipurpose exercise machines discussed above are generally effective for their intended purposes, including shoulder and elbow exercises it is perceived that they have numerous shortcomings. The present invention addresses these problems. In particular, a preferred shoulder/elbow machine according to the invention includes a "floating" hand grip sturdily mounted on an exercise arm; and is a fully adjustable, portable and stable exercise machine suitable for use with any type of therapy table or any type of bed or chair. Preferred machines according to the invention include a simple, lightweight and compact means for selectively engaging casters with the floor surface. Other advantages and features of the present invention are described below.